JJ Keller Entry Level Driver Training For CDL (Commercial Driver’s License) Practice Test

The first step in starting a tractor-trailer engine is to apply the parking brake. This safety measure ensures that the vehicle remains stationary and prevents any unintended movement while starting the engine. By securing the vehicle in place, the driver promotes safety for themselves and anyone working around the vehicle. It's a critical practice that helps avoid accidents and injuries that could occur if the vehicle were to roll unexpectedly as the engine is started. While other steps like turning on the ignition, checking fluid levels, and engaging the clutch are essential to the operation of the tractor-trailer, they should be conducted with the vehicle secured. By applying the parking brake first, the driver lays the foundation for a safe and proper start to their pre-trip routine.